There is a growing need for staple removing devices, as staplers is now a popular consumer item. Many people use staplers, from builders, office workers, students at school, to the people at home. While stapling sheets or solid substrates such as wood, there are times when the staple needs to be removed because the staple is stapled in the wrong place, or there was a need to add more sheets, or was not stapled properly such that staple was warped and would not hold properly.
Many devices were created to remove staples. A pry type staple remover uses a chisel-like tongue to wedge under the staple's arms to twist and dig the arms up, and the tongue is wedged under the staple crossbar to lift and dig the whole staple up. Removing the staples in this fashion requires a lot of time, a large number of actions, and it usually damages the substrate. Also, it is sometimes unsuccessful in completely removing the staple, requiring fingernails or pliers to complete the job.
A double jawed pincer type staple remover uses a pair of opposed arms with curved teeth members that wedges under the staple crossbar to lift staple up. This type of remover suffers from a disadvantage of requiring a large amount of force to operate because the operator has to press the arms together at the position where there is no mechanical leverage advantage from the opposed arms. Thus this remover is only useful for small office type staples, and not heavy-duty staples. This large force results in unpredictable behavior, since a small variation in the angle of application will result in uneven forces distributed across staple crossbar so that only one arm is removed. Also, when the substrate is especially thing and pliable, such as in the case of only a few sheets stapled together, removing the staple using the double jawed pincer type often makes a mess of the substrate and tears the substrate with the staple still attached to the torn pieces of substrate.
U.S. Pat. No. 5,195,724 issued on Mar. 23, 1993 to Koo, U.S. Pat. No. 5,657,965 issued on Aug. 19, 1997 to Aria, and U.S. Pat. No. 6,772,996 issued on Aug. 10, 2004 to Carlston et al. all describe staple removing devices with similar staple removing principles, the double jawed pincer type staple remover described above. Staple removers using this principle have the disadvantage of requiring high amount of manual force from the fingers to operate. These types of staple removers also have the disadvantage of in inadequate support to the substrate. Due to the high and difficult to control forces required from the fingers, and from the many moving parts moving in contact with the substrate, the paper is frequently damaged during the staple removing operation.
U.S. Pat. No. 5,605,320 issued on Feb. 25, 1997 to Crawford describes a staple remover having a first member with two spaced apart prongs inserted under the staple crossbar, and a second member pivotally connected to the first member, and a nose member. The nose member, upon relative movement between the first and second member, deforms the staple to allow the staple legs to be withdrawn substantially from the substrate. This type of staple remover also suffers from inadequate support to the substrate. The substrate is frequently dented and damaged by the nose member when the said nose member moves below the two spaced apart prongs and into the substrate. At the same time, the substrate near the staple legs is also damaged due to inadequate support, because the two spaced apart prongs are lifted from the substrate to naturally oppose the nose member as it presses into the substrate.
U.S. Pat. No. 5,996,969 issued in Dec. 7, 1999 to Johnston et al, describes a staple remover including a clamping mechanism that secures one staple leg to the remover, enabling extracting of that leg. The staple is removed by prying and lifting, similar to the pry-type remover described above. The prying action naturally produces a gap between the staple and substrate, and therefore also suffers from the disadvantage of inadequate support to fragile substrates such as paper.
U.S. Pat. No. 5,653,424 issued on Aug. 5, 1997 to Khan, describes a staple remover with a tongue-like tapered blade and a slidable claw member. The blade is slidably inserted under the staple arm causing the staple to unclenth. A slidable claw member is used to push the staple into a storage compartment. This staple remover requires the remover to slide a relatively long distance until the wider end of the tapered tongue unclenches the staple.
A levered pry type stapler remover uses a tongue extending from a lever member pivotally connected to a base member to wedge under the staple crossbar. Pushing down the lever member forces the tongue upwards, lifting the staple from the substrate. However, this type of remover does not do anything to prevent the substrate from being damaged or torn.
Thus it is desirable to have a staple removing device that does not require excessive force to operate, minimises damage to the substrate, and doesn't require sliding the remover long distances.